U.S. patent application number 10/172006 was filed with the patent office on 2002-12-19 for vibration control apparatus for vehicle having electric motor.
This patent application is currently assigned to NISSAN MOTOR CO., LTD.. Invention is credited to Ito, Ken, Karikomi, Takaaki.
Application Number | 20020190683 10/172006 |
Document ID | / |
Family ID | 19023460 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020190683 |
Kind Code |
A1 |
Karikomi, Takaaki ; et
al. |
December 19, 2002 |
Vibration control apparatus for vehicle having electric motor
Abstract
In a vibration control apparatus for a vehicle driven by an
electric motor at least, a first target torque is calculated from a
vehicle operating condition such as an accelerator opening, and a
second target torque is calculated from at least a sensed motor
speed by using a model H(s)/Gp(s) composed of a transfer
characteristic H(s) which is greater than or equal to a transfer
characteristic Gp(s) in an order difference between the order of a
denominator and the order of a numerator. A torque control section
controls the motor to bring an actual output torque of the motor
closer to a command motor torque determined from the first and
second target torque.
Inventors: |
Karikomi, Takaaki;
(Kanagawa, JP) ; Ito, Ken; (Tokyo, JP) |
Correspondence
Address: |
McDERMOTT, WILL & EMERY
600 13th Street, N.W.
Washington
DC
20005-3096
US
|
Assignee: |
NISSAN MOTOR CO., LTD.
|
Family ID: |
19023460 |
Appl. No.: |
10/172006 |
Filed: |
June 17, 2002 |
Current U.S.
Class: |
318/632 ;
903/917 |
Current CPC
Class: |
Y10S 903/917 20130101;
Y02T 10/7258 20130101; Y02T 10/72 20130101; G05D 19/02
20130101 |
Class at
Publication: |
318/632 |
International
Class: |
G05D 023/275 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 2001 |
JP |
2001-183519 |
Claims
What is claimed is:
1. A vibration control apparatus for a vehicle powered by an
electric motor, the vibration control apparatus comprising: a motor
speed sensor to sense an actual motor speed of the electric motor;
a first target torque setting section to set a first target torque
in accordance with vehicle information on a vehicle operating
condition; a motor speed estimating section which includes a filter
having a model Gp(s) of a transfer characteristic between a vehicle
torque input and a motor speed, and which is arranged to receive a
command motor torque and to calculate an estimated motor speed of
the electric motor from the command motor torque with the filter; a
deviation calculating section determining an input quantity from a
deviation of the actual motor speed from the estimated motor speed;
a second target torque setting section including a filter having a
model H(s)/Gp(s) composed of a transfer characteristic H(s) which
is greater than or equal to the model Gp(s) in an order difference
between the order of a denominator and the order of a numerator,
the second target torque setting section being arranged to receive
the input quantity from the deviation calculating section and to
calculate, as an output quantity, a second target torque from the
input quantity with the filter having the model H(s)/Gp(s); a
command torque calculating section to calculate the command motor
torque by addition of the first target torque and the second target
torque, and to deliver the command motor torque to the motor speed
estimating section; and a motor torque controlling section to
control the electric motor to bring an actual output torque of the
electric motor closer to the command motor torque.
2. The vibration control apparatus as claimed in claim 1, wherein
the first target torque setting section comprises: a steady target
torque setting section to set a steady target torque in accordance
with the vehicle information; and a target torque modifying section
to receive the steady target torque and to set the first target
torque by passing the steady target torque through a filter having
a characteristic Gm(s)/Gp(s) composed of an ideal model Gm(s)
representing a transfer characteristic between a vehicle torque
input and a motor speed, and the model Gp(s).
3. The vibration control apparatus as claimed in claim 1, wherein
the vibration control apparatus further comprises: a command engine
torque setting section to set, in accordance with the vehicle
information, a command engine torque for an engine of the vehicle
which is powered by the electric motor and the engine; and an
engine and motor speed correcting section having a filter GE(s)
modeled on a delay from a change in the command engine torque to a
resulting change in an actual engine torque, and a transfer
characteristic G'm(s) between an engine torque and an engine and
motor speed, the engine and motor speed correcting section being
arranged to receive the command engine torque from the command
engine torque setting section and to calculate an engine and motor
correction speed from the command engine torque; and wherein the
deviation calculating section is configured to calculate the input
quantity to the second target setting section by adding the engine
and motor correction speed to the deviation of the actual motor
speed from the estimated motor speed.
4. The vibration control apparatus as claimed in claim 3, further
comprising: a command engine torque modifying section to receive
the command engine torque from the command engine torque setting
section, and to calculate a modified command engine torque by
passing the command engine torque through a filter G'm/Gp(s)
composed of the transfer characteristic G'm(s) and Gp(s); and an
engine controlling section to control the engine in accordance with
the modified command engine torque.
5. The vibration control apparatus as claimed in claim 3, wherein
the model Gp(s) includes a parameter which represents an inertia of
a prime mover including the electric motor and engine and which is
varied in accordance with a connecting condition of the engine in
the prime mover.
6. The vibration control apparatus as claimed in claim 1, wherein
the model Gp(s) includes a parameter which is varied in accordance
with a speed ratio of the vehicle.
7. The vibration control apparatus as claimed in claim 1, wherein
the second target torque setting section comprises a band-pass
filter having the transfer characteristic H(s).
8. The vibration control apparatus as claimed in claim 7, wherein
the transfer characteristic H(s) of the band-pass filter is so set
that a damping characteristic on a low-pass side and a damping
characteristic on a high-pass side are substantially equal to each
other, and a resonance frequency of a drive system is located
substantially at a middle of a pass-band of the transfer
characteristic H(s).
9. The vibration control apparatus as claimed in claim 1, wherein
the model Gp(s) is a mathematical model obtained by subjecting a
transfer characteristic derived from an equation of motion to
pole-zero cancellation.
10. A vibration control apparatus for a vehicle powered by an
electric motor, the vibration control apparatus comprising: a motor
speed sensor to sense an actual motor speed of the electric motor;
a first target torque setting section to set a first target torque
in accordance with vehicle information on a vehicle operating
condition; a motor speed calculating section which includes a
filter having a desired model Gm(s) of a transfer characteristic
between a vehicle torque input and a motor speed, and which is
arranged to receive a command motor torque and to calculate a
desired motor speed of the electric motor from the command motor
torque with the filter; a subtracting section to calculated a
deviation of the actual motor speed from the desired motor speed; a
second target torque setting section including a filter having a
model H(s)/Gp(s) composed of a transfer characteristic H(s) which
is greater than or equal to a transfer characteristic Gp(s) in an
order difference between the order of a denominator and the order
of a numerator, the second target torque setting section being
arranged to receive the deviation from the subtracting section and
to calculate a second target torque from the deviation by using the
filter having the model H(s)/Gp(s); a command torque calculating
section to calculate the command motor torque by addition of the
first target torque and the second target torque, and to deliver
the command motor torque to the motor speed calculating section;
and a motor torque controlling section to control the electric
motor to bring an actual output torque of the electric motor closer
to the command motor torque.
11. A vibration control apparatus for a vehicle having a prime
mover including an electric motor, the vibration control apparatus
comprising: first calculating means for calculating a first target
torque in accordance with vehicle information on a vehicle
operating condition; second calculating means for calculating a
second target torque in accordance with a sensed motor speed by
using a torque determining model H(s)/Gp(s) composed of a transfer
characteristic H(s) which is greater than a transfer characteristic
Gp(s) in an order difference between the order of a denominator and
the order of a numerator; third calculating means for calculating a
command motor torque from the first target torque and the second
target torque; and controlling means for controlling the electric
motor to bring an actual output torque of the electric motor closer
to the command motor torque.
12. The vibration control apparatus as claimed in claim 11, wherein
the first calculating means includes a means for calculating the
first target torque in accordance with the sensed motor speed and a
driver's accelerator input.
13. The vibration control apparatus as claimed in claim 11, wherein
the second calculating means comprises: means for calculating an
estimated motor speed of the electric motor from the command motor
torque by using a speed estimating model having a transfer
characteristic between a vehicle torque input and a motor speed;
means for determining an input quantity from a deviation of the
actual motor speed from the estimated motor speed; and means for
calculating the second target torque from the input quantity by
using the torque determining model H(s)/Gp(s).
14. A vibration control process for a vehicle having a prime mover
including an electric motor, the vibration control process
comprising: calculating a first target torque in accordance with
vehicle information on a vehicle operating condition; calculating a
second target torque from a sensed motor speed of the electric
motor, by using a model H(s)/Gp(s) composed of a transfer
characteristic H(s) which is greater than or equal to a transfer
characteristic Gp(s) in an order difference between the order of a
denominator and the order of a numerator; and calculating a command
motor torque from the first target torque and the second target
torque, to control the electric motor to bring an actual output
torque of the electric motor closer to the command motor torque.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a vibration control
apparatus for a vehicle having an electric motor, and more
specifically to such a vibration control apparatus for restraining
hunching in torque.
[0002] A Published Japanese Patent Application Kokai Publication
No. 2001-45613 shows a vibration control apparatus for a vehicle
driven by an electric motor.
SUMMARY OF THE INVENTION
[0003] It is an object of the present invention to provide
vibration control apparatus and/or process capable of reducing
vibrations reliably in a vehicle powered by an electric motor.
Another object is to provide vibration control apparatus and/or
process capable of reducing vibrations securely even in a situation
in which an accelerator pedal is depressed from a stop state or a
deceleration state.
[0004] According to one aspect of the present invention, a
vibration control apparatus for a vehicle powered by an electric
motor (6) comprises: (a) a motor speed sensor to sense an actual
motor speed of the electric motor; (b) a first target torque
setting section to set a first target torque in accordance with
vehicle information on a vehicle operating condition; (c) a motor
speed estimating section which includes a filter having a model
Gp(s) of a transfer characteristic between a vehicle torque input
and a motor speed, and which is arranged to receive a command motor
torque and to calculate an estimated motor speed of the electric
motor from the command motor torque with the filter; (d) a
deviation calculating section determining an input quantity from a
deviation of the actual motor speed from the estimated motor speed;
(e) a second target torque setting section including a filter
having a model H(s)/Gp(s) composed of a transfer characteristic
H(s) which is greater than or equal to the model Gp(s) in an order
difference between the order of a denominator and the order of a
numerator, the second target torque setting section being arranged
to receive the input quantity from the deviation calculating
section and to calculate, as an output quantity, a second target
torque from the input quantity with the filter having the model
H(s)/Gp(s); (f) a command torque calculating section to calculate
the command motor torque by addition of the first target torque and
the second target torque, and to deliver the command motor torque
to the motor speed estimating section; and (g) a motor torque
controlling section to control the electric motor to bring an
actual output torque of the electric motor closer to the command
motor torque.
[0005] According to another aspect of the present invention, a
vibration control apparatus for a vehicle powered by an electric
motor comprises: a motor speed calculating section which includes a
filter having a desired model Gm(s) of a transfer characteristic
between a vehicle torque input and a motor speed, and which is
arranged to receive a command motor torque and to calculate a
desired motor speed of the electric motor from the command motor
torque with the filter; a subtracting section determining a
deviation of the actual motor speed from the estimated motor speed;
and a second target torque setting section including a filter
having a model H(s)/Gp(s) composed of a transfer characteristic
H(s) which is greater than or equal to a transfer characteristic
Gp(s) in an order difference between the order of a denominator and
the order of a numerator, the second target torque setting section
being arranged to receive the deviation from the subtracting
section and to calculate a second target torque from the deviation
with the filter having the model H(s)/Gp(s).
[0006] According to still another aspect of the present invention,
a vibration control apparatus for a vehicle having a prime mover
including an electric motor, the vibration control apparatus
comprises: (a) first calculating means for calculating a first
target torque in accordance with vehicle information on a vehicle
operating condition; (b) second calculating means for calculating a
second target torque in accordance with a sensed motor speed by
using a torque determining model H(s)/Gp(s) composed of a transfer
characteristic H(s) which is greater than a transfer characteristic
Gp(s) in an order difference between the order of a denominator and
the order of a numerator; (c) third calculating means for
calculating a command motor torque from the first target torque and
the second target torque; and (d) controlling means for controlling
the electric motor to bring an actual output torque of the electric
motor closer to the command motor torque.
[0007] According to still another aspect of the present invention,
a vibration control process for a vehicle having a prime mover
including an electric motor, the vibration control process
comprises: (a) calculating a first target torque in accordance with
vehicle information on a vehicle operating condition; (b)
calculating a second target torque from a sensed motor speed of the
electric motor, by using a model H(s)/Gp(s) composed of a transfer
characteristic H(s) which is greater than or equal to a transfer
characteristic Gp(s) in an order difference between the order of a
denominator and the order of a numerator; and (c) calculating a
command motor torque from the first target torque and the second
target torque, to control the electric motor to bring an actual
output torque of the electric motor closer to the command motor
torque.
[0008] The other objects and features of this invention will become
understood from the following description with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a schematic view showing a vibration control
apparatus according to a first embodiment of the present
invention.
[0010] FIG. 2 is a block diagram showing a motor torque setting
section and a vibration control section in the vibration control
apparatus of FIG. 1.
[0011] FIG. 3 is a graph showing a map of a relation among motor
speed, accelerator opening and output torque, used in the vibration
control apparatus of FIG. 1.
[0012] FIG. 4 is a schematic view for illustrating an equation of
vehicle motion, used to determine a model in the vibration control
apparatus of FIG. 1.
[0013] FIG. 5 is a block diagram of a vibration control section
rearranged as an equivalent from the vibration control section of
FIG. 2, so as to prevent drift.
[0014] FIG. 6 is a block diagram of a vibration control section
rearranged as an equivalent from the vibration control section of
FIG. 2, so as to prevent control delay.
[0015] FIG. 7 is a graph showing a transfer characteristic H(s)
used in the vibration control apparatus of FIG. 1.
[0016] FIGS. 8A and 8B are graphs showing a step response of
earlier technology and a step response obtained by the vibration
control apparatus according to the first embodiment,
respectively.
[0017] FIG. 9 is a schematic view showing a vibration control
apparatus according to a second embodiment of the present
invention.
[0018] FIG. 10 is a block diagram showing an engine torque setting
section and a vibration control section in the vibration control
apparatus of FIG. 9.
[0019] FIGS. 11A, 11B, 11C and 11D are graphs showing,
respectively, engine torque input, motor torque input (feedback
compensation), motor and engine angular speed, and vehicle
longitudinal acceleration in the vibration control apparatus of the
second embodiment.
[0020] FIG. 12 is a schematic view showing a vibration control
apparatus according to a third embodiment of the present
invention.
[0021] FIG. 13 is a block diagram showing an engine torque setting
section and a vibration control section in the vibration control
apparatus of FIG. 12.
[0022] FIGS. 14A, 14B and 14C are block diagrams showing variations
of the third embodiment.
[0023] FIG. 15 is a block diagram showing a motor torque setting
section and a vibration control section in a vibration control
apparatus according to a fourth embodiment of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0024] FIG. 1 shows a vibration control apparatus according to a
first embodiment of the present invention. A vibration control
apparatus 10 is connected with a motor 6 for driving a vehicle 7.
Vibration control apparatus 10 includes a motor rotational angle
sensor (means for sensing a rotational speed of motor 6), and an
accelerator opening sensor 2 for sensing an opening degree of an
accelerator pedal of the vehicle (or driver's accelerator
input).
[0025] Vibration control apparatus 10 further includes a motor
torque setting section (means for setting a first target torque) 3
for setting a target motor torque (first target torque T*) in
accordance with the accelerator opening sensed by accelerator
opening sensor 2 and the motor speed sensed by motor angle sensor
1; a vibration control section 4; and a motor torque control
section (means for controlling the motor torque) 5.
[0026] Vibration control section 4 receives the first target torque
T* from motor torque setting section 3 and data on the motor angle
sensed by motor angle sensor 1; calculates a command motor torque
T'* in accordance with these input data items; and delivers command
motor torque T'* to motor torque control section 5.
[0027] Motor torque control section 5 controls motor 6 so as to
bring the output torque of motor 6 equal to command motor torque
T'* dictated by vibration control section 4.
[0028] FIG. 2 shows more in detail motor torque setting section 3
and vibration control section 4 in the form of block diagram. Motor
torque setting section 3 includes: a torque map (means for setting
a steady target torque) 11 having a preset relation, for a
plurality of accelerator opening values, between the speed of motor
6 and the output torque of motor 6, as shown in FIG. 3; and a
control block (means for modifying the target torque) 12 having a
transfer characteristic Gm(s)/Gp(s). In this transfer
characteristic, Gp(s) is a model representing a transfer
characteristic between a torque input to the vehicle and the motor
rotational speed; and Gm(s) is a model (ideal model) representing a
desired response of the torque input to the vehicle and motor
rotational speed.
[0029] Vibration control section 4 includes: a control block (means
for estimating a motor speed) 13 having the above-mentioned
transfer characteristic Gp(s); a subtracter (subtracting means) 14
for calculating a deviation between the output of control block 13
and the motor rotational speed; a control block 15 for receiving
the deviation determined by subtracter 14 as an input and producing
a filter output with a transfer characteristic H(s)/Gp(s); and an
adder (means for calculating a command motor torque) 16 for adding
the output of control block 15 and first target torque T*. Transfer
characteristic H(s) is so set that a difference between the order
(or degree) of a denominator of H(s) and the order (or degree) of a
numerator of H(s) is equal to or greater than a difference between
the order (or degree) of a denominator of transfer characteristic
Gp(s) and the order (or degree) of a numerator of Gp(s). In this
example, subtracter 14 serves as a section to determine an input
quantity to control block 15, and the input quantity is equal to
the deviation of the actual motor speed from the estimated motor
speed.
[0030] Model Gp(s) in the form of the transfer characteristic of
the vehicle torque input and motor speed is given in the following
manner. FIG. 4 is a schematic view for illustrating equation of
motion of a driving torsional vibration system. The example of FIG.
4 employs the following notation.
[0031] Jm: Inertia of motor
[0032] Jw: Drive wheel inertia
[0033] M: Mass of vehicle
[0034] KD: Torsional rigidity of drive system
[0035] KT: Coefficient regarding friction between tire and road
surface
[0036] N: Overall gear ratio
[0037] r: Tire loaded radius
[0038] .omega.m: Angular speed of motor
[0039] Tm: Torque of motor
[0040] TD: Drive wheel torque
[0041] F: Force applied on vehicle
[0042] V: Vehicle speed
[0043] .omega.w: Drive wheel angular speed
[0044] From FIG. 4, the following equation of motion is
obtained.
Jm.multidot..omega.*m=Tm-TD/N (1)
2Jw.multidot..omega.*w=TD-rF (2)
MV*=F (3)
TD=KD.intg.(.omega.m/N-.omega.w)dt (4)
F=KT(r.omega.w-V) (5)
[0045] The asterisk * added to a reference represents time
differentiation.
[0046] From these equations (1).about.(5), the transfer
characteristic Gp(s) from the motor torque to the motor speed is
obtained as follows:
Gp(s)=(b.sub.3s.sup.3+b.sub.2s.sup.2+b.sub.1s+b.sub.0)/s(a.sub.4s.sup.3+a.-
sub.3s.sup.2+a.sub.2s+a.sub.1) (6)
a.sub.4=2Jm.multidot.Jw.multidot.M (7)
a.sub.3=Jm(2Jw+Mr.sup.2)KT (8)
a.sub.2=(Jm+2Jw/N.sup.2)M.multidot.KD (9)
a.sub.1=(Jm+2Jw/N.sup.2+Mr.sup.2/N.sup.2)KD.multidot.KT (10)
b.sub.3=2Jw.multidot.M (11)
b.sub.2=(2Jw+Mr.sup.2)KT (12)
b.sub.1=M.multidot.KD (13)
b.sub.0=KD.multidot.KT (14)
[0047] Examination of pole and zero point in the transfer
characteristic expressed by equation (6) shows that one pole and
one zero point assume values which are very close to other. This
means that .alpha. and .beta. in the following equation (15) assume
values very close to each other.
Gp(s)=(s+.beta.)(b.sub.2's.sup.2+b.sub.1's+b.sub.0')/s(s+.alpha.)(a.sub.3'-
s.sup.2+a.sub.2's+a.sub.1') (15)
[0048] Therefore, the transfer characteristic Gp(s) in the form of
[second order]/[third order] as in the following equation (16) is
obtained by pole zero cancellation (approximation of
.alpha.=.beta.) in equation (15).
Gp(s)=(b.sub.2's.sup.2+b.sub.1's+b.sub.0')/s(a.sub.3's.sup.2+a.sub.2's+a.s-
ub.1') (16)
[0049] To implement equation (16) by microcomputer operations, in
this example, Z transform and discretization are performed by using
equation (17).
s=(2/T).multidot.{(1-Z.sup.-1)/(1+Z.sup.-1)} (17)
[0050] The transfer characteristic Gp(s) expressed by equation (17)
contains a genuine integral term. Therefore, vibration control
section 4 of FIG. 2 is equivalent transformed to a vibration
control section 21 as shown in FIG. 5. That is, vibration control
section 4 is transformed into an arrangement including a control
block 22 having a transfer characteristic H(s) and a control block
23 having a transfer characteristic H(s)/Gp(s). This arrangement
helps prevent drift.
[0051] In vibration control sections 4 and 21 shown in FIGS. 2 and
5, there is formed an algebraic loop which requires dead time for
discretization. However, the system of this embodiment can prevent
control delay due to dead time by using a vibration control section
26 including a control block 24 having a transfer characteristic
1/(1-H(s)) and a control block 25 having a transfer characteristic
H(s)/Gp(s), as shown in FIG. 6.
[0052] When the speed ratio of the vehicle is variable, this
vibration control apparatus can provide accurate vibration control
performance irrespective of changes in the speed ratio by varying
each constant or parameter in transfer characteristic Gp(s) in
dependence on the speed ratio.
[0053] Transfer characteristic H(s), when set as a band-pass
filter, serves as a feedback element reducing only vibrations. In
this case, the maximum effects can be achieved when the filter
characteristic is set as shown in FIG. 7. In the characteristic of
H(s) shown in FIG. 7, the damping characteristic is approximately
equal between the low-pass side and the high-pass side, and the
torsional resonance frequency of the drive system is set at or
about the middle of the pass band on the logarithmic axis (log
scale). For example, H(s) can be set as a first order high-pass
filter as expressed by the following equation by using the
torsional resonance frequency fp of the drive system and an
arbitrary constant value k.
H(s)=.tau.Hs/{(1+.tau.Hs).multidot.(1+.tau.Ls)} (18)
[0054] where .tau.L=1/(2.pi.fHC), fHC=kfp, .tau.H=1/(2.pi.fLC) and
fLC=fp/k.
[0055] The effect can be increased by increasing the constant k
tough there is limitation of constant k to maintain the stability
of the control system. In some cases, it is possible to set
constant k to a value smaller than or equal to one. In the same
manner as mentioned before, Z transformation and descritization are
performed.
[0056] FIGS. 8A and 8B show variation of longitudinal acceleration
(G) with respect to speed for comparison of vibration control
between a control model of earlier technology and the control model
according to this embodiment of the invention. As shown in FIG. 8B,
the vibration control system using the control model according to
this embodiment can reduce vibrations sufficiently in starting the
vehicle, as compared to the results of the earlier technology shown
in FIG. 8A. In order to remove a frequency component in torsional
vibration causative of hunting produced with respect to a target
torque of an electric motor, a vibration control system of earlier
technology is arranged to add, to a map representing a relation
between speed and torque, a filter having a transfer function
Gm(s)/Gp(s) composed of a desired response Gm(s) and a
characteristic Gp(s) of the controlled system. Thus, the vibration
control system of earlier technology is arranged to suppress
hunting in a creep operation of a vehicle, and moreover to enable
smooth acceleration of the vehicle by realizing a sharp torque rise
in response to driver's accelerator operation.
[0057] However, the element Gm(s)/Gp(s) functions as a feed forward
compensator in torque control, so that the vibration control effect
(to reduce hunting) tends to be insufficient due to influence of
looseness in a gear system in a situation in which an accelerator
pedal is depressed in a vehicle rest state or vehicle deceleration
state. By contrast, the vibration control apparatus according to
the first embodiment can reduce vibrations sufficiently in
acceleration from the rest state or deceleration state.
[0058] Vibration control apparatus 10 according to the first
embodiment functions to detect vibrations due to disturbance torque
and unmatch of vehicle model and cancel the vibrations by feedback
compensation. Therefore, the vibration control performance is
sufficient even in the rest state of the vehicle, and in
accelerating operation caused by depression of the accelerator
pedal during deceleration. Moreover, this system can reduce
vibrations even when torsional vibrations are excited by an
external factor.
[0059] FIGS. 9 and 10 show a vibration control apparatus 31
according to a second embodiment of the present invention.
Vibration control apparatus 31 is for a vehicle including, as prime
mover, engine 33 and electric motor 6 (vehicle of a motor assist
type). As shown in FIG. 9, vibration control apparatus 31 includes
motor angle sensor 1, accelerator opening sensor 2, motor toque
setting section 3, vibration control section 32 and motor torque
control section 5. Vibration control apparatus 31 further includes
engine torque setting section (means for setting command engine
torque) 8 and engine torque control section 9.
[0060] Engine torque setting section 8 sets a command engine torque
TE* in accordance with the motor speed sensed by motor angle sensor
1 and the accelerator opening sensed by accelerator opening sensor
2.
[0061] Engine torque control section 9 controls engine 33 in
accordance with command engine torque TE* so as to bring the output
torque of engine 33 to command engine torque TE*.
[0062] FIG. 10 shows more in detail engine torque setting section 8
and vibration control section 32 shown in FIG. 9. Engine torque
setting section 8 includes a map 8a having a relation between the
motor speed and engine output torque, for data of accelerator
opening. Map 8a receives, as inputs, the speed of motor 6 and data
on the accelerator opening, and delivers, as an output, the command
engine torque TE* corresponding to these inputs.
[0063] Vibration control section 32 includes three control blocks
34, 35 and 36, and two adders 37 and 38.
[0064] Control block (an engine and motor speed correcting section)
34 has a transfer characteristic G'm(s).multidot.GE(s). G'm(s) is a
target response (ideal model) of the vehicle torque input and motor
rotational speed. GE(s) is a delay model representing a delay from
the output of command engine torque TE* to the generation of actual
engine torque.
[0065] Control block 35 has a transfer characteristic Gp(s), and
control block 36 has a transfer characteristic H(s)/Gp(s). Transfer
characteristic Gp(s) is arranged to alter a parameter representing
the inertia (moment of inertia) of the prime mover (engine and
motor) in accordance with a connecting condition of a connecting
device, such as an electromagnetic clutch, for making connection of
engine, to obtain accurate vibration control performance
irrespective of the connecting condition of the engine.
[0066] Adder 37 adds the output of control block 34 and the output
of control block 35 together, and moreover subtract the data of the
sensed actual motor speed. The resulting signal is delivered to
control block 36. Adder 37 serves as summing means for algebraic
sum or a deviation calculating section to determine an input
quantity to be inputted to the second target torque setting section
(36).
[0067] Adder 38 adds the output signal of control block 36 serving
as the second target torque setting section, and the first command
torque T1* supplied from motor torque setting section 3.
[0068] The thus-constructed vibration control apparatus according
to the second embodiment provides vibration control performance in
vehicle starting operation as in the first embodiment even in a
motor assist type vehicle.
[0069] FIGS. 11A.about.11D show various characteristic of vibration
control apparatus 31. FIGS. 11A, 11b, 11c and 11D show,
respectively, time variations of engine torque input, motor torque
input (feedback compensation), motor & engine angular speed and
vehicle longitudinal acceleration. In these figures, broken lines
show characteristic with no vibration control, and solid lines show
characteristics obtained by vibration control according to the
second embodiment. These characteristics reveal the effects by
vibration control apparatus 31, of reducing vibrations during a
vehicle starting operation.
[0070] FIGS. 12 and 13 shows a vibration control apparatus 41
according to a third embodiment of the invention. Vibration control
apparatus 41 differs from vibration control apparatus 31 of the
second embodiment, in an engine torque setting section 42, as shown
in FIG. 13, including a map 42a and a control block 43 for
modifying a command engine torque TE* obtained from map 42a.
[0071] As shown in FIG. 13, engine torque setting section 42
includes a control block 43 having a transfer characteristic
G'm(s)/Gp(s). This control block 43 receives command engine torque
TE* from map 42a and determines a modified command torque TE'* by
modifying command engine torque TE*. Modified command torque TE'*
is supplied to engine 33.
[0072] The thus-constructed vibration control apparatus 41 can
provide comparable effects to the second embodiment with less
feedback compensation quantity though the computation load is
increased, and thereby the vibration control apparatus 41 can
improve the controllability.
[0073] Though the vehicle is of the motor assist type in the second
and third embodiments, the present invention is applicable to
vehicles of various other types. In the case of a vehicle equipped
with a transmission for changing or varying the speed ratio, or a
parallel hybrid vehicle having a device for connecting and
disconnecting an engine, the vibration control apparatus can
provide good control performance by varying or adjusting constants
(Jm, N) in transfer characteristic Gp(s) (cf. equation (6)).
[0074] Within the concept of the present invention, there are many
other conceivable applications with equivalent mathematical
configurations. It is possible to employ an arrangement shown in
FIG. 14A, 14B or 14C. Moreover, the present invention is not
limited to numerical values employed in the illustrated examples.
Values should be adjusted appropriately in accordance with the
characteristic of an actual vehicle.
[0075] FIG. 15 shows a part of a vibration control apparatus
according to a fourth embodiment of the invention. The vibration
control apparatus of the fourth embodiment is substantially
identical in arrangement as a whole to the apparatus shown in FIG.
1, except for motor torque setting section 51 and vibration control
section 52. FIG. 15 shows motor torque setting section 51 and
vibration control section 52 according to the fourth embodiment.
Motor toque setting section 51 does not have control block 12 of
FIG. 2, so that the first target torque T1* outputted from motor
torque setting section 51 is equal to the output of map 5la.
[0076] Vibration control section 52 includes two control blocks 53
and 54, a subtracter 55 and an adder 56. Control block 53 has a
transfer characteristic Gm(s) and control block 54 has a transfer
characteristic H(s)/Gp(s). Subtracter 55 calculates a deviation
between the output of control block 53 and the motor speed. Adder
56 adds first target torque T1* and the output of control block
54.
[0077] The vibration control apparatus according to the fourth
embodiment can restrain vibrations excited by first target torque
T1* and vibrations excited by nonlinearity such as looseness or
disturbance, only with the feedback control. It is possible to
arrange the vibration control apparatus of the fourth embodiment so
that there is further provided the engine torque setting section as
in the second or third embodiment.
[0078] Section 3 or 51 can serve as first calculating means for
calculating a first target torque in accordance with vehicle
information on a vehicle operating condition. Sections 13, 15, 22,
23, 25, 34, 35, 36, 37, 53, 54 or 55 can serve as second
calculating means for calculating a second target torque in
accordance with a sensed motor speed by using a torque determining
model H(s)/Gp(s) composed of a transfer characteristic H(s) which
is greater than a transfer characteristic Gp(s) in an order
difference between the order of a denominator and the order of a
numerator. Sections 16, 24, 38 or 56 can serve as third calculating
means for calculating a command motor torque from the first target
torque and the second target torque. Sections 5 or 9 can serve as
controlling means for controlling the electric motor to bring an
actual output torque of the electric motor closer to the command
motor torque. Sections 13 and/or 53 can serve as means for
calculating an estimated motor speed of the electric motor from the
command motor torque by using a speed estimating model (Gp(s),
Gm(s)). Sections 14, 37 or 55 can serve as means for determining an
input quantity from a deviation of the actual motor speed from the
estimated motor speed. Sections 15, 36 or 54 can serve as means for
calculating the second target torque from the input quantity by
using the torque determining model H(s)/Gp(s).
[0079] This application is based on a prior Japanese Patent
Application No. 2001-183519. The entire contents of the prior
Japanese Patent Application No. 2001-183519 with a filing date of
Jun. 18, 2001 are hereby incorporated by reference.
[0080] Although the invention has been described above by reference
to certain embodiments of the invention, the invention is not
limited to the embodiments described above. Modifications and
variations of the embodiments described above will occur to those
skilled in the art in light of the above teachings. The scope of
the invention is defined with reference to the following
claims.
* * * * *